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Rhiw Saeson Caerau is a prehistoric hillfort situated in Wales and protected as a scheduled monument by Cadw under reference GM065. The site occupies ground underlain by the South Wales Upper Coal Measures Formation, a Westphalian-age geological sequence comprising mudstone, siltstone, sandstone, coal, ironstone and ferricrete. This substantial bedrock creates the elevated terrain that made the location strategically valuable for the Iron Age community that fortified it.
The hillfort's position on Coal Measures geology reflects the natural landscape opportunities available to its builders. The ferricrete layers within the bedrock sequence may have weathered into iron-rich soils visible on the surface, whilst the underlying coal measures indicate the area's later industrial importance, though this postdates the monument by many centuries. The solid geology provided a stable foundation for ramparts and internal structures.
As a defended settlement, the hillfort would have served as a focal point for the surrounding population, offering both refuge and a visible assertion of territorial control. The monument remains a substantial landscape feature today, preserving evidence of Iron Age social organisation and settlement hierarchy in the Welsh uplands. Its protection reflects the significance of such fortified sites to understanding prehistoric Britain's later periods.
Rhiw Saeson Caerau is a scheduled monument protected by Cadw under reference GM065. View the official record →
Rhiw Saeson Caerau is a prehistoric hillfort situated in Wales and protected as a scheduled monument by Cadw under reference GM065.
Rhiw Saeson Caerau dates from the prehistoric period, and is classified as a hillfort. It is one of over 32,000 scheduled monuments protected across the UK.
Rhiw Saeson Caerau is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is GM065.
Several scheduled monuments lie within 10 km, including Y Gaer (8.4 km), Cottrell Ringwork (8.6 km), Cottrell Castle Mound (8.8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Rhiw Saeson Caerau's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Rhiw Saeson Caerau stands on South Wales Upper Coal Measures Formation, bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.